Maroon Bells, in the distance, see from Maroon Lake. Photograph: Alamy

Crested Butte: Hiking among wildflowers

The splendid panoramas of jagged summits would be reason enough to hike the West Maroon Pass trail. But the seas of rainbow-coloured wildflowers that carpet these valleys in July and August mean hikers risk sensory overload. Nowhere else in Colorado will you find such vibrant concentrations of high-alpine blooms, which is why the nearby town of Crested Butte is known as the state's wildflower capital. The route starts at Schofield Pass, 14 miles north-west of town, and follows the east fork of the Crystal river through meadows of waist-high columbine, larkspur and lupin. After 4.5 miles and 2,090 feet of climbing, hikers reach West Maroon Pass and its 360-degree vistas of Pyramid Peak, the Maroon Bells, and snow-capped mountains in all directions. • +1 970 925 3445, fs.fed.us/r2/whiteriver. Best season: July-September, peaking around 21 July

Fruita: Cross-country mountain biking

Photograph: Alamy

The quaint town of Fruita, 19 miles from the Utah border, rivals Moab as a mountain-biking hotspot. Smooth single track gives way to tight curves and rocky steeps that appeal to intermediate and expert riders, and the scenery is outstanding, with weathered badlands and red-rock canyons cut by the Colorado river. A network north of Fruita called 18 Road Trails includes convenient – if primitive – campsites. But the best views are from Horsethief Bench trail (part of the Kokopelli network south of town), which hugs the rim of Ruby Canyon.• Trail maps and information: gjmountainbiking.com/fruita. Rentals and equipment: Over the Edge Sports, Fruita, otesports.com. The best season is March-November; summers are exceedingly hot. Camping: $10 a night (+1 970 244 3000, blm.gov, reservations not accepted)

Winter Park: Downhill mountain biking

This ski resort 90 minutes west of Denver is Colorado's best destination for downhillers, because the designers who built Whistler's renowned bike park recreated their magic here. Trestle Bike Park has 42 miles of lift-served trails suitable for all abilities, with smooth options for beginners and huge jumps for pros. Many have bailout routes offering easy alternatives for bikers whose courage fails. But the hardest trails require total commitment from expert riders, who roll along narrow wooden planks suspended high above the ground and soar off tall jumps. Rentals and instruction are available.• +1 970 726 1564, trestlebikepark.com. Lift tickets from $24 (adult), $23 (over 65, child 13-18); $16 (child 11-12). Open mid May - 14 October

Breckenridge: Climbing Quandary Peak

Colorado is the highest state in the US, thanks in part to its 54 "fourteeners" (mountains over 14,000ft, or 4,267m). Many trekkers strive to collect all 54, and Quandary Peak (14,265ft) is a good starter. It requires no ropework or technical scrambling – just the burn of oxygen-starved muscles. The waymarked three-mile route begins at 10,900ft, from a trailhead eight miles south of Breckenridge. Hikers pass a cluster of abandoned mines before gaining the peak's east ridge, near the treeline at 11,700ft. From there, mountain views abound. Be sure to leave the peak by noon to avoid afternoon lightning.• Best season: July-September. +1 970 468 5400, fs.usda.gov/recarea/whiteriver

Gunnison: Fishing the Taylor river

Photograph: Alamy

The quarter-mile section of the Taylor river below Taylor Park Dam is known as the Hog Trough because it has the biggest trout in Colorado. Rainbows weighing up to 15lb lurk here, so crowds are common, and catching trophies is no easy task. To fool these wary fish, anglers need flawless technique to dead-drift tiny nymphs through challenging currents. Fishing along the 12 miles of public water downstream of the Hog Trough is also excellent, and offers solitude.• +1 970 641 0471, fs.fed.us/r2/gmug. Best season: year-round. State fishing licence required ($9 a day, wildlife.state.co.us)

Denver: Watching concerts at Red Rocks

Photograph: Alamy

Ever since U2 made their Under a Blood Red Sky concert video here in 1983, the Red Rocks outdoor amphitheatre has gained worldwide fame for its scenic backdrop. Massive wings of wrinkled red stone flank the stage, and audiences look out over city lights flickering on the plain below. Big musical acts (such as BB King, Keith Urban and Queens of the Stone Age) appear during the summer concert lineup but there are also drop-in yoga sessions, and hiking and biking trails wind through sculpted rocks and wildflowers.• 18300 West Alameda Parkway, Morrison, +1 720 865 2494, redrocksonline.com. Best season: June-September. Entrance to the park is free: it's open 5am-11pm except on concert dates, when the amphitheatre closes in the afternoon

Steamboat Springs: Hot air ballooning

Photograph: Paul Hanna/Reuters/Corbis

There's no better way to appreciate the scale of Colorado's vast mountains and valleys than from the air, and the gentle currents around Steamboat Springs make this one of the best places in the state to board a balloon. Launches take place in the windless early-morning hours, when mists blanket the sweeping ranchlands. Floating high above town, passengers see cattle grazing in the open meadows, the Yampa river snaking among the grasses, and 10,500ft peaks rolling away in all directions. • +1 970 879 7219, wildwestballooning.com. Best season: June-October, though flights are offered year-round. Flights (45 minutes): adult $225, over-65 $210, child (3-12) $140

Buena Vista: Rafting the Arkansas river

Whitewater Rafting on Arkansas River Photograph: Rob Howard/Corbis

The Arkansas river through Browns Canyon is Colorado's most popular whitewater destination, and for good reason. This 12-mile stretch of rapids enters a roadless zone of beautiful mountains and canyons. At the start of the trip, several fourteeners tower impressively above the water. Next, the river plunges into a granite gorge where bald eagles and bighorn sheep can be spotted, and class III and IV rapids provide additional thrills. The biggest, Zoom Flume, continues for a quarter of a mile. Book a half-day trip with River Runners, a guide company conveniently headquartered at the landing stage and serving up tasty fish tacos at its Riverside Grill.• Buena Vista, +1 800 723 8987, whitewater.net. Best season: May-July. From $63.75 (adult), $53.63 (under-12)

Cortez: Hiking Mesa Verde

Photograph: Mark Miller/Getty Images

Some of the most fascinating remnants of America's earliest inhabitants are found at Mesa Verde national park, where the Anasazi or Ancestral Pueblo people built elaborate cities between 600AD and 1300. Some of the park's 5,000 known archaeological sites are open to hikers. Guided tours climb ladders and crawl through tunnels to Cliff Palace and Balcony House, constructed in stone alcoves high above the canyon floor. You won't need a guide on the Petroglyph Point or Nordenskiold Site No 16 trails, where hikers can experience solitude among the primitive paintings and ruins.• nps.gov/meve. Best season: June-August. Park entrance from $10 a vehicle (valid for seven days)

Estes Park: Wildlife watching

Photograph: Alamy

No need to bring binoculars to Moraine Park, a high-alpine valley where elk let hikers approach within 100ft. This wildlife sanctuary is in Rocky Mountain national park, where hunting is outlawed and a network of roads and footpaths leads visitors right to elk strongholds. The scenic drive along Bear Lake Road skirts broad meadows full of elk grazing beneath jagged peaks. Hikers who follow the footpath along the Big Thompson river gain an even closer view. At the Moraine Park Campground (+1 518-885-3639, reservations recommended, pitches from $14 a night) you can overnight within sight of the herds. In the mating season, mid-September to mid-October, the sound of bull elk bugling fills the air.• nps.gov/romo. Best season: June-November. Park entrance $20 a vehicle (valid for seven days)